My team at Duke University worked with Raj Aggarwal of University of Akron and Krisztina Holly at the University of Southern California to research the backgrounds of 549 entrepreneurs whose companies had made it past the begging-for-seed-money stage and were generating real revenue. We found that only 9% had raised any angel capital, and 11% had raised venture capital after they had grown. There was some overlap between these two groups.

In other words, nine out of ten successful startups did it all on their own.

Where did the funding come from for those companies that failed to attract an outside investment? For the vast majority—70%—of successful entrepreneurs starting their first companies, it was from personal savings. A much smaller number raised money from business partners, bank loans, friends and family, and other sources.